cardiac cycle

CARDIAC CYCLE

• one cardiac cycle : one complete cycle that encompasses atrial and ventricle contraction and relaxation

• 

• P wave	atrial depolarization & contraction	fills the ventricles	cuspid valves open while valves of vena cava and pulmonary veins are closed
  QRS complex	atrial repolarization and relaxation & simultaneous ventricular depolarization and contraction	empties the ventricles	cuspid valves are closed while semilunar valves are open
  T wave	ventricular repolarization and relaxation	heart relaxes	cuspid and semilunar valves are closed
  pause	myocardium at rest	atria fill after a pause of some length	valves of vena cava and pulmonary veins open so atria can fill

Chronic obstructive pulmonary disease

Hypothermia

External signs of hypothermia

• indistinct, blurred margin of pink or brownish pinkish
• usually over the extensor surface of the knee,elbow and hip joint
• not in area where hypostasis might occur
• may have necrosis or blister
• may have frost bites
  

1. Pinkish margin occurs because in hypothermia, cells have a lesser degree of oxygen uptake, thus the pinkish margin id due to oxygenated blood that remains in the blood vessel

Internal signs of hypothermia

• gastric ulceration : blackish or brownish
• patches of fat necrosis
• haemorrhagic pancreatitis
• diffuse lung haemorrhage and pulmonary odema